func (p *Pinger) recvICMP(conn *icmp.PacketConn, recv chan<- *packet, ctx *context, wg *sync.WaitGroup) { p.debugln("recvICMP(): Start") for { select { case <-ctx.stop: p.debugln("recvICMP(): <-ctx.stop") wg.Done() p.debugln("recvICMP(): wg.Done()") return default: } bytes := make([]byte, 512) conn.SetReadDeadline(time.Now().Add(time.Millisecond * 100)) p.debugln("recvICMP(): ReadFrom Start") _, ra, err := conn.ReadFrom(bytes) p.debugln("recvICMP(): ReadFrom End") if err != nil { if neterr, ok := err.(*net.OpError); ok { if neterr.Timeout() { p.debugln("recvICMP(): Read Timeout") continue } else { p.debugln("recvICMP(): OpError happen", err) p.mu.Lock() ctx.err = err p.mu.Unlock() p.debugln("recvICMP(): close(ctx.done)") close(ctx.done) p.debugln("recvICMP(): wg.Done()") wg.Done() return } } } p.debugln("recvICMP(): p.recv <- packet") select { case recv <- &packet{bytes: bytes, addr: ra}: case <-ctx.stop: p.debugln("recvICMP(): <-ctx.stop") wg.Done() p.debugln("recvICMP(): wg.Done()") return } } }